Device for providing an internal combustion engine with fuel, comprising a fuel filter

ABSTRACT

The device includes a closure element ( 20 ), which closes an opening ( 18 ) of a fuel tank ( 12 ) and has a cup-shaped receptacle ( 22 ), which opens toward the outside of the fuel tank ( 12 ), contains the fuel filter ( 24 ), and can be closed by a cover element ( 36 ), which can be detachably fastened to the closure element ( 20 ). An elastic sealing ring ( 46 ), which is clamped between the closure element ( 20 ) and the cover element ( 36 ), seals the receptacle ( 22 ). In the vicinity of the sealing ring ( 46 ), the closure element ( 20 ) has at least one opening ( 52 ) via which the receptacle ( 22 ) communicates with the interior of the fuel tank ( 12 ). When the cover element ( 36 ) is fastened onto the closure element ( 20 ), the sealing ring ( 46 ), starting from a non-deformed original shape, is elastically deformed in such a way that it closes the at least one opening ( 52 ). When the cover element ( 36 ) is detached from the closure element ( 20 ), the sealing ring ( 46 ) returns to its original shape in which it unblocks the at least one opening ( 52 ). This produces a pressure relief into the interior of the fuel tank ( 10 ) when the cover element ( 36 ) is detached.

PRIOR ART

[0001] The invention is based on a fuel supply device of an internalcombustion engine with a fuel filter, as generically defined by thepreamble to claim 1.

[0002] EP 0 612 919 A1 has disclosed a device of this kind. This devicehas a closure element, which closes an opening of a fuel tank and whichhas a cup-shaped receptacle into which the fuel filter is inserted. Thereceptacle can be closed from the outside of the fuel tank by means of acover element, which can be detachably fastened to the closure element.An elastic sealing ring is clamped between the cover element and theclosure element and seals the receptacle. Fuel, which is supplied to theinternal combustion engine under pressure by a delivery unit, flowsthrough the fuel filter. The pressure in the delivery system is usuallymaintained even when the delivery unit is not running; this pressurealso prevails in the fuel filter receptacle. When the fuel filter isreplaced, for which the cover element is detached from the closureelement, pressurized fuel can escape, which is a danger to the personwho is replacing the filter and also represents a fire hazard.

ADVANTAGES OF THE INVENTION

[0003] The fuel supply device according to the invention, with thecharacterizing features of claim 1, has the advantage over the prior artthat when the cover element is detached from the closure element, thesealing ring unblocks the at least one opening connecting the receptacleto the interior of the fuel tank, which produces a pressure relief intothe fuel tank so that no pressurized fuel escapes from the receptacle.There is therefore no danger to the person who is replacing the filterand no fire hazard.

[0004] Advantageous embodiments and modifications of the deviceaccording to the invention are disclosed in the dependent claims.

DRAWINGS

[0005] An exemplary embodiment of the invention is shown in the drawingsand will be explained in detail in the subsequent description.

[0006]FIG. 1 schematically depicts a fuel supply device of an internalcombustion engine,

[0007]FIG. 2 shows a detail of the device in a view according to thearrow II in FIG. 1,

[0008]FIG. 3 shows an enlargement of a detail labeled III in FIG. 1,with a cover element fastened in place, and

[0009]FIG. 4 shows the detail when the cover element is detached.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT

[0010] FIGS. 1 to 4 show a fuel supply device of an internal combustionengine 10 of a motor vehicle. The engine 10 has an injection system thatinjects fuel into the cylinders of the engine. The motor vehicle has afuel tank 12 that contains a collecting receptacle 14. The collectingreceptacle 14 contains a delivery unit 16, which is comprised of a pumppart and a drive part in the form of an electric motor. When running,the delivery unit 16 aspirates fuel from the collecting receptacle 14and supplies it under pressure to the internal combustion engine 10. Ajet pump 17 delivers fuel from the fuel tank 12 into the collectingreceptacle 14.

[0011] The fuel tank 12 has an opening 18, through which the collectingreceptacle 14 can be inserted into it. The opening 18 is closed in asealed fashion by a flange-like closure element 20, which is fastened tothe fuel tank 12 in a manner that is not shown in detail. A cup-shapedreceptacle 22 for a fuel filter 24 is embodied on the closure element 20and points into the interior of the fuel tank 12. The receptacle 22 isopen toward the outside of the fuel tank 12. The fuel filter 24 isinserted into the receptacle 22 from the outside of the fuel tank 12.The fuel filter 24 has an elastically deformable flange 26 at its upperand lower end. When the fuel filter 24 is inserted into the receptacle22, its flanges 26 rest with initial stress in the radial directionagainst the circumference wall and the bottom 23 of the receptacle 22and produce seals there.

[0012] The side of the closure element 20 pointing into the interior ofthe fuel tank 12 is provided with a fitting 28, which communicates withthe receptacle 22. The fitting 28 has a hydraulic line 30 slid onto it,which is connected to the outlet of the delivery unit 16. The fuelsupplied by the delivery unit 16 travels through the line 30 and thefitting 28 to the dirty side of the fuel filter 24, which is formedbetween its circumference and the circumference wall of the receptacle22. The fuel flows through the fuel filter 24 in a radially inwarddirection, to its clean side. The flanges 26 of the fuel filter 24produce a seal between the clean side and the dirty side. A pressurerelief valve 32 can be disposed at the bottom 23 of the receptacle 22and when a predetermined pressure on the clean side of the fuel filter24 is exceeded, this pressure relief valve 32 opens and allows fuel tobe discharged into the fuel tank 12. Preferably, the closure element 20can be comprised of plastic and be produced by means of injectionmolding so that the receptacle 22 and the fitting 28 can be easilyproduced to be of one piece with it.

[0013] The receptacle 22 can be closed by a cover element 36, which canbe detachably fastened to the closure element 20. For example, the coverelement 36 can be fastened to the closure element 20 by means of abayonet connection 38. The bayonet connection 38 can be embodied as abayonet catch in which a number of bayonet hooks 40 are embodieddistributed over the circumference of the cover element 36, only one ofwhich is shown in FIGS. 1 and 2. The closure element 20 is provided witha flange 21, which has a number of radial recesses 42 embodied on itsinner rim, corresponding to the number and arrangement of the bayonethooks 40, and in the circumference direction adjacent to these recesses42, ramps 44 are embodied on the inside of the flange 21 oriented towardthe closure element 20. When the cover element 36 is fastened in place,it is placed onto the closure element 20 in the direction of thelongitudinal axis 25 of the receptacle 22, in a rotational position inwhich its bayonet hooks 40 pass through the recesses 42, and then thecover element 36 is rotated into a locking position in which its bayonethooks 40 slide onto the ramps 44, which causes the cover element 36 tobe pulled toward the closure element 20 in direction of the longitudinalaxis 25.

[0014] Alternatively, the cover element 36 can also be fastened to theclosure element 20 by means of a screw connection. In this instance, theclosure element 20 can have a with an external thread and the coverelement 36 can have a shoulder with an internal thread, which is screwedonto the external thread of the closure element 20. When the coverelement 36 is screwed in, it is pulled toward the closure element 20 indirection of the longitudinal axis 25 of the receptacle 22. It is alsopossible for a separate securing ring with an internal thread to beused, which encompasses the cover element 36 and is screwed onto theexternal thread of the closure element 20.

[0015] A fitting 37 is provided on the cover element 36, protrudingoutward from it; the cover element 36 is preferably comprised of plasticand is produced by means of injection molding and the fitting 37 isformed onto and of one piece with it. The cover element 36 rests againstthe upper flange 26 of the fuel filter 24 with an initial stress andconsequently produces a seal between the clean side and the dirty sideof the fuel filter 24. The clean side of the fuel filter 24 communicateswith the fitting 37 to which a line leading to the internal combustionengine 10 is connected, through which the fuel supplied by the deliveryunit 16 travels to the engine 10.

[0016] In order to seal the receptacle 22 in relation to the outside, anelastic sealing ring 26 is clamped between the cover element 36 and theclosure element 20. The cover element 36 rests against the closureelement 20 by means of the sealing ring 46 and inside the sealing ring46, an axial gap 47 remains between the cover element 36 and the closureelement 20. For example, the cross section of the sealing ring 46 canhave an original shape that is approximately circular and can becomprised of fuel-resistant rubber or elastomer. On its side orientedtoward the closure element 20, the cover element 36 has acircumferential annular groove 48 in which the sealing ring 46 isdisposed. On its side oriented toward the cover element 36, the closureelement 20 has a circumferential annular rib 50, disposed opposite fromthe outer flank of the annular groove 48 of the cover element 36. Inlieu of the annular rib 50, the closure element 20 can also have anannular groove, which is disposed opposite the annular groove 48 of thecover element 36. The closure element 20 has at least one opening 52through which the receptacle 22 communicates with the interior of thefuel tank 12. The at least one opening 52 is disposed inside the sealingring 46 and directly adjacent to it.

[0017] The sealing ring 46 is disposed between the closure element 20and the cover element 36 and is clamped and therefore elasticallydeformed during the fastening of the cover element 36, due to themovement of the cover element 36 directed toward the closure element 20.FIG. 3 shows the cover element 36 in the position in which it isfastened to the closure element 20 and the sealing element 46 is in itselastically deformed state, when it is pressed flat and is consequentlylarger in the radial direction than in its original shape. In thiselastically deformed state, the sealing ring 46 covers over the at leastone opening 52 of the closure element 20 so that the receptacle 22 doesnot communicate with the interior of the fuel tank 12. The pressurizedfuel supplied by the delivery unit 16 consequently flows through thefuel filter 24 and travels out through the fitting 37.

[0018] The pressure in the delivery system between the delivery unit 16and the internal combustion engine 10 is maintained even when the engine10 and the delivery unit 16 are not running. This permits a rapidstarting of the engine 10. Consequently, there is always an overpressurein the receptacle 22 in comparison to the ambient pressure. Particles inthe fuel flowing through the fuel filter 24, which are held back by thefuel filter 24 so that they do not travel into the engine 10, can causethe fuel filter 24 to become clogged, thus necessitating itsreplacement. This can be done easily by detaching and removing the coverelement 36 from the closure element 20 so that the fuel filter 24 can beremoved from the receptacle 22 and a new fuel filter can be inserted.

[0019] When the cover element 36 is detached from the closure element20, it is moved away from the closure element 20 so that the sealingring 46 returns to its approximately circular original shape, which isdepicted in FIG. 4. In its original shape, the sealing ring 46 does notcover the at least one opening 52 of the closure element 20, thusunblocking it, allowing the receptacle 22 to communicate with theinterior of the fuel tank 12 by means of the gap 47 and the at least oneopening 52. In the process of detaching the cover element 36, thereceptacle 22 is consequently pressure relieved into the interior of thefuel tank 12 by means of the at least one opening 52 so that in thesubsequent removal of the cover element 36, no pressurized fuel canescape from the receptacle 22.

1. A fuel supply device of an internal combustion engine with a fuelfilter, having a closure element (20) that closes an opening (18) of afuel tank (12) and has a cup-shaped receptacle (22), which opens towardthe outside of the fuel tank (12) and contains the fuel filter (24),having a cover element (36), which can close the receptacle (22) and isdetachably fastened to the closure element (20), and having an elasticsealing ring (46), which is clamped between the closure element (20) andthe cover element (36) and seals the receptacle (22), characterized inthat in the vicinity of the sealing ring (46), the closure element (20)has at least one opening (52) via which the receptacle (22) communicateswith the interior of the fuel tank (12), that when the cover element(36) is fastened onto the closure element (20), the sealing ring (46),starting from a non-deformed original shape, is elastically deformed insuch a way that it closes the at least one opening (52), and that whenthe cover element (36) is detached from the closure element (20), thesealing ring (46) returns to its original shape in which it unblocks theat least one opening (52).
 2. The device according to claim 1,characterized in that the cover element (36) and/or the closure element(20) has an annular groove (48) in which the sealing ring (46) isdisposed.
 3. The device according to claim 1 or 2, characterized in thatthe cover element (36) can be fastened to the closure element (20) bymeans of a bayonet connection (38).
 4. The device according to one ofclaims 1 to 3, characterized in that the receptacle (22) is filled withpressurized fuel.